This invention relates generally to apparatus for testing electrical equipment and particularly to built-in-test apparatus for performing on-line tests and providing a diagnostic capability of a digital power system stabilizer for an electrical turbine generator system.
A power system stabilizer (PSS) is an auxiliary control device which is used in connection with large power turbine generator excitation systems to increase the damping of the power system electromechanical oscillations. The details and operation of a power system stabilizer are well known to those skilled in the art and various types of implementations have been effected. In general, however, a power system stabilizer provides an adjustable amount of gain and phase lead between a signal proportional to generator shaft speed and generator output voltage utilizing an automatic voltage regulator and generator exciter. In the past, the power system stabilizer has been implemented by analog techniques using analog filters whose characteristics are designed to provide the desired gain and phase response. More recently, the state of the art has moved towards digital types of controls including the implementation of digital power system stabilizers.
Widespread utilization of power system stabilizers has been hampered, however, by the need for periodic testing of the apparatus to verify its operational status. These tests have typically required the services of a qualified expert to perform frequency response measurements at the site of the generator utilizing complex test equipment.